I swapped the gears from 3.31 to 3.73. I have looked everywhere to see if I have to change something to correct the speedo. Please help.

 

is your spedo acting up? i havent heard anything about needed to do that for that kind of gear change

 

It just dont feel like the right speed.

 

Any gear change will require a speedometer adjustment.

2005-2009 Mustangs require you to adjust the parameters in the tune. Should be the same for 2012 as well. I see you're using a Bama tune, so I'm going to assume you probably have an SCT tuner. Rear gearing is often left adjustable in their tunes. If not, give Bama/AM a call.

 

Thanks for the info. I was hoping it was an electronic change and not a speedo gear change.